Exercise apparatus capable of measuring force that user applies on

ABSTRACT

The present invention provides an exercise apparatus for allowing a user to perform an exercise. The user drives at least one moving member to rotate a flywheel. The flywheel must overcome a resistance generated by a magnetic field generating module during rotation. In a preferred embodiment, the magnetic field generating module is supported by a flexible support member and tends to restore to an initial position. The magnetic field generating module will be pushed by the flywheel in a rotational direction of the flywheel and to generate a corresponding displacement. The displacement or the deformation of the support member is measured by a first measuring device so as to appropriately calculate the output force of the user, and further obtains power, metabolic equivalent or calorie consumption rate if correlated with rotational speed of the flywheel or corresponding parameters measuring by a second measuring device.

BACKGROUND 1. Field of the Invention

The present invention relates to an exercise apparatus. More particularly, the present invention relates to an exercise apparatus capable of measuring force that a user applies on.

2. Description of the Related Art

Nowadays, various exercise apparatuses such as treadmills, stationary bikes, elliptical trainers, stair climbing machines, rower machines, and most of them can display a variety of numerical information for a user during exercise such as difficulty/resistance level of movement, speed/frequency of movement, elapsed time, accumulated distance/number of steps, accumulated calorie consumption for presenting the use's exercise condition. Furthermore, some exercise apparatuses will display instant exercise power (the basic concept is the amount of energy/calorie consumption per unit time of the user, usually in watts), and/or metabolic equivalent (MET, the basic concept is the ratio of metabolic rate during a specific exercise to a reference metabolic rate at rest as sitting quietly) for allowing the user to quickly know the current exercise. The electric treadmill or the stair climbing machine usually obtains the aforementioned metabolic equivalent according to a set of established standards directly from the running speed (and slope) of the running belt or the stair. For example, an activity with a MET value of 3.6, such as walking 5.5 km/h (3.4 mph). If necessary, the metabolic equivalent and the user's weight (or an assumed average body weight) could be substituted into a conversion formula or use a conversion table to obtain the exercise power. On the other hand, for the exercise apparatuses such as stationary bikes, elliptical trainers, rower machines, non-electric treadmills that require the user to drive moving members (e.g. pedals, handles, running belts) for movement, the exercise power can be understood as a work done by the user in a unit time on the aforementioned moving members or the entire motion system. In contrast, the metabolic equivalent is generally obtained by substituting the exercise power and the user's weight (or an assumed average body weight) into a conversion formula or using a conversion table. The higher/lower the values of the exercise power and the metabolic equivalent, the stronger/weaker the intensity of the user's movement and the faster/slower the calorie consumption rate, which is an important indicator for sport management.

However, for the exercise apparatuses that require a user to drive a moving member to perform the exercise, the exercise power and the metabolic equivalent displayed on most of the current exercise apparatuses during exercise are not actual values really derived from measuring the rate at which the user works on the motion system (e.g. by measuring the torque and rotational speed of the crank shaft of the stationary bike to calculate the rotational power of the crank shaft driven by the user), but using the so-called lookup table to calculate estimated values appropriately. Specifically, in the case of a stationary bike that can be used to adjust the pedal rotation resistance, the manufacturer will test the prototype of the bike at the development stage first, driving the pedal set of the bike with a driving device (e.g. a hydraulic motor), and then measuring and recording the output power of the driving device at different levels of pedal resistance and various rotational speeds to create a two-dimensional array of power contrast table and/or a corresponding metabolic equivalent contrast table for use in pre-existing control systems of the same product. Accordingly, in a bike having the same motion system and resistance system, when the user drives the pedals to rotate at a rotational speed and resistance level, it is presumed that the exercise power of the user is equivalent to the output power of the driving device at the same rotational speed and resistance level. Therefore, it is able to appropriately obtain the corresponding exercise power and/to metabolic equivalent through the aforementioned contrast table.

Relative to table lookup method, recently, some exercise apparatuses will actually measure the mechanical work or power of the motion system during operation to actually calculate the exercise output or exercise power of the user. For example, two annular gratings may be coaxially mounted to the crank shaft of the stationary bike, and obtaining the successive pulses generated as the two annular gratings rotate with the crank shaft by a fixed sensor. The phase difference of the two groups of pulse signals reflects the distortion of the crank shaft under the driving torque, and thereby calculate the torque of the crank shaft (proportional to the exercise output of the user), and it can be measured with rotational speed to calculate the rotational power (proportional to the exercise power of the user). But the implementation of this method is complex, high precision and high cost.

Another possible method such as a strain gauge may be mounted to the radial spokes of the driving pulley of the stationary bike for measuring the deformation of the spokes, such pulley is a transmission component between the crank shaft (drive end) and the flywheel (load end). The torque of the crank shaft can be calculated based on the degree of blending deformation of the radial spokes, and the rotational power can be calculate with the measurement of the rotational speed. Since the measuring device (strain gauge) is arranged on the rotating member (pulley), the measuring signal must be transmitted via a wireless transmission module or a slip ring and slip ring bushes to the operational control unit on the fixed frame, which has high cost and unstable signal transmission problems.

SUMMARY

The main object of the present invention provides an exercise apparatus, which is capable of practically measuring specific parameters corresponding to the force endured by the motion system during exercise for relatively accurately measuring the output force that the user applies to the motion system or further obtaining motion rate, metabolic equivalent, calorie consumption rate, etc. Furthermore, the present invention is applicable to any exercise apparatus with a flywheel and a resistance system, such device for measuring the output force of the user is relatively simple and low cost.

According to one aspect of the present invention, an exercise apparatus comprises a frame, at least one moving member, a flywheel, a transmission mechanism, a base, a support member and a magnetic field generating device. The moving member is driven by a user to be movable with respect to the frame when the user performs the exercise. The flywheel is pivotally mounted to the frame. The transmission mechanism is connected between the moving member and the flywheel for driving the flywheel to rotate as the moving member is driven by the user. The base is mounted to the frame. The support member has a first portion and a second portion. The first portion is connected to the base and the second portion is movable from an initial position to other positions with respect to the base. The support member is affected by an elastic force. The elastic force is increased as the second portion of the support member departs from the initial position and biasing the second portion of the support member to return to the initial position. The magnetic field generating device is fixed to the second portion of the support member and being adjacent to the flywheel. The magnetic field generating device is configured to generate a magnetic field for exerting a drag force opposing rotational motion of the flywheel. A first measuring device is configured to measure a value of a first parameter which represents displacement of the second portion of the support member departing from the initial position.

Preferably, the exercise apparatus further comprises a second measuring device for measuring a value of a second parameter. The second parameter represents a rotational speed of the flywheel. An operational control unit is configured to calculate values of power, metabolic equivalent or calorie consumption rate by using at least two parameter values including the values of the first parameter and the second parameter.

Preferably, the magnetic field generating device comprises at least one permanent magnet. The base is movable with respect to the frame between a first position in which the magnetic field generating device is close to the flywheel and a second position in which the magnetic field generating device is away from the flywheel.

Preferably, the magnetic field generating device comprises at least one electromagnet. The exercise apparatus further comprises an electric current control device for controlling electric current applied to the electromagnet.

Preferably, the support member is flexible, and the elastic force is generated by deformation of the support member between the second portion and the first portion as the second portion is departed from the initial position. The first parameter corresponds to the deformation of the support member between the second portion and the first portion. The support member is plate-shaped, having a surface that is deformed flexibly as the second portion departs from the initial position. The first measuring device comprises a strain gauge mounted on the surface of the support member for sensing the deformation of the surface of the support member.

Preferably, the first portion of the support member is movably connected to the base for allowing the support member to move with respect to the base. The exercise apparatuses further comprises an elastic member. The elastic member has one end connected to the base or the frame and the other end connected to the support member. The elastic member is deformed as the second portion of the support member departs from the initial position and provides the elastic force to the support member.

Further benefits and advantages of the present invention will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic drawing of an exercise apparatus in accordance with a first preferred embodiment of the present invention;

FIG. 2 is a schematic drawing of the measuring system of the first embodiment and illustrates the operation of the measuring system for measuring the torque of the flywheel;

FIG. 3 is similar to FIG. 2, but the magnetic field generating module is closer to the flywheel;

FIG. 4 is a schematic drawing of a measuring system in accordance with a second preferred embodiment of the present invention;

FIG. 5 is similar to FIG. 4, illustrating the operation of the measuring system for measuring the torque of the flywheel;

FIG. 6 is a schematic drawing of a measuring system in accordance with a third preferred embodiment of the present invention; and

FIG. 7 is a schematic drawing of a measuring system in accordance with a fourth preferred embodiment of the present invention.

DETAIL DESCRIPTION

In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically depicted in order to simplify the drawings.

Referring to FIG. 1, which shows a constitution of an exercise apparatus in accordance with a first preferred embodiment of the present invention (note: the figure only briefly depicted parts related to the technical contents of the present invention directly). For example, in the preferred embodiment, the exercise apparatus is a general stationary bike. The stationary bike includes a frame (not shown), a pedal assembly 10, a flywheel 20 and a belt mechanism 30. The frame is served as a fundamental base for installation of other components. The pedal assembly 10 has a crank axle 12 pivotally mounted to the frame, two crank arms 14 fixed at two opposite ends of the crank axle 12, and two opposite pedals 16 respectively mounted to the outer ends of the two crank arms 14. The flywheel 20 is pivotally mounted to the frame as well. The axle of the flywheel 20 and the crank axle 12 are parallel and spaced apart in a predetermined distance. FIG. 1 shows that the flywheel 20 is located directly behind the crank axle 12 (the right side in the figure). The belt mechanism 30 has a large belt pulley 32 coaxially secured to the crank axle 12, a small belt pulley 34 coaxially secured to the flywheel 20, and a driving belt 36 mounted around the large belt pulley 32 and the small belt pulley 34.

The pedal assembly 10, the flywheel 20 and the belt mechanism 30 together constitute the motion system of the stationary bike, and the two pedals 16 each regards as a moving member for allowing a user to perform pedaling exercise. In general, the user will sit on the seat (not shown) of the stationary bike, grip the handle (not shown) of the stationary bike, and then step on the pedals 16 with two feet alternately to drive the pedals 16 to rotate forwardly in a predetermined circular path. Besides, the crank axle 12 is driven by the crank arms 14 to revolve around the axle itself on the frame. By the transmission of the belt mechanism 30, when the crank axle 12 is revolved, the flywheel will be revolved around the axle itself on the frame at a relatively faster speed, namely, when the user pedals the pedals 16, it is actually forced to drive the whole motion system to be operated.

According to one aspect of the present invention, in the stationary bike motion system shown in FIG. 1, the crank arms 14 and the crank axle 12 of the pedal assembly 10, and even the large belt pulley 32, the driving belt 36 and the small belt pulley 34 of the belt mechanism 30, which are regarded as a transmission mechanism for transmitting the power from the pedals 16 to the flywheel 20. It should be noted that, unlike one-way transmission mode in general bicycles for outdoor riding (e.g. one-way clutch mechanism for a bicycle freewheel hub), in the structure of the aforementioned stationary bike, no matter the pedals are rotated forwardly or reversely, it will drive the flywheel 20 to rotate in the same direction.

The transmission mechanism shown in FIG. 1, especially the belt mechanism 30, is just a simple and typical structure. In practice, the transmission mechanism of the stationary bike may be slightly more complicated or in various types. For example, the belt mechanism 30 may have a guide pulley/tension pulley, may adopt sprockets and a chain to replace the belt pulleys and the driving belt, may adopt two-stage transmission, may adopt gear transmission system, etc. However, no matter what structure is used, the function of the transmission mechanism is to transmit the rotational power of the pedals 16 to the flywheel 20 by a predetermined transmission ratio eventually, namely, when the user forces the pedals 16, the flywheel 20 is rotated at the same time and its rotational speed and torque respectively correspond to the rate and the output ratio of the pedaling movement. In short, the specific structure of the transmission mechanism is not limited in the present invention.

In general, the flywheel 20 is made of metal and has a predetermined mass. The main function of the flywheel 20 is to generate a rotational inertia while rotating for allowing the motion system to work smoothly. In the present invention, the flywheel 20 is also a resistance system (magnetic resistance system) of the exercise apparatus and a part of measuring system which will be described later.

As shown in FIG. 1, the stationary bike further comprises a display device 42 for showing the information for the user such as various LCD, LED devices, and an input device 44 for allowing the user to input a command such as various pressed keys, touch control devices. In practice, the display device 42 and the input device 44 are disposed on a console (not shown) of the stationary bike and located in front of the user who is exercising. The display device 42 and the input device 44 are not limited in the present invention.

The stationary bike further comprises an operational control unit 50 such as a programmable control circuit which includes a microcontroller unit (MCU). In practice, the programmable control circuit is generally installed in the console (at least core portion of the programmable control circuit). It is able to process any judgement, calculation and command according to the predetermined program, data, real time command, signals, etc. The operational control unit 50 is electrically connected to the display device 42 and the input device 44 respectively for controlling the display content of the display device 42, receiving and processing the input commands through the input device 44.

As shown in the lower right portion of FIG. 1, the stationary bike further comprises a base 62, a support member 64 and a magnetic field generating module 66. The base 62 is mounted on the frame and movable with respect to the frame between a first position and a second position. In the preferred embodiment of the present invention, as depicted in FIG. 1, the base 62 is a sliding block that located directly behind the flywheel 20 (right side in the figure), it is capable of sliding forth and back on the frame substantially in the radial direction of the flywheel 20. The front and rear of its range of movement are respectively defined as the first position and the second position. Furthermore, there is a position control device 46 for driving the base 62 to move and position the base 62 in a predetermined position within the range of movement. The support member 64 has a first portion (right end in the figure) and a second portion (left end in the figure) opposite to each other. The first portion of the support member 64 is fixed to the base 62, the second portion of the support member 64 is suspended between the base 62 and the flywheel 20 as a cantilever end, and the whole support member 64 extends substantially horizontally at the height of the axis of the flywheel 20. The magnetic field generating module 66 is fixed to the second portion of the support member 64 such that the magnetic field generating module 66 is supported by the support member 64 at a position adjacent to the rear end of the flywheel 20. The magnetic field generating module 66 is configured to generate a magnetic field for exerting a drag force opposing the rotational motion of the flywheel 20. For example, in the preferred embodiment, the magnetic field generating module 66 has a plurality of permanent magnets, one half of which is located at one side in the axial direction of the flywheel 20 and arranged so that the north pole faces toward the flywheel 20, and the other half is located at the opposite side of the flywheel 20 and arranged so that the south pole faces toward the flywheel 20. Each magnet is opposite to the other magnet at the opposite side. Therefore, parts of the magnetic field lines of the magnetic field generated by the permanent magnets will pass through the flywheel 20 along the axial direction of the flywheel 20. Based on eddy-current effect, it will generate a drag force on the flywheel 20 contactlessly for resisting the rotational motion of the flywheel 20. Accordingly, when the user rotates the pedals 16 to drive the flywheel to rotate, it is necessary to overcome the drag force applied on the flywheel 20 by the magnetic field generating module 66.

The position control device 46 is able to control the position the base 62 relative to the frame. For example, the position control device 46 may include an electric motor (not shown) and a motor-driven gear set (not shown). Correspondingly, the base 62 is screwed by a screw rod 48 in a front-rear direction. The screw rod 48 has one end coupled to an output end of the gear set. When the electric motor is running in a forward or backward direction, the screw rod is driven to rotate forward or backward on its own axis via the gear set to drive the base 62, the support member 64 and the magnetic field generating module 66 to move forward or backward. As shown in FIG. 3 relative to FIG. 2, the magnetic field generating module 66 moves closer to the axis of the flywheel 20 as the base 62 moves more forward (toward the first position), namely the more working area of the permanent magnets against the flywheel 20, the more magnetic flux passes through the flywheel 20 to increase the drag force. In contrast, the magnetic field generating module 66 moves away from the axis of the flywheel 20 as the base 62 moves more backward (toward the second position), namely the working area of the permanent magnets against the flywheel would be decreased such that the magnetic flux passing through the flywheel is reduced to decrease the drag force. In another embodiment of the present invention (not shown), the base is pivotally mounted to the frame, and it is controlled to rotate between a first position and a second position (angular position) to drive the magnetic field generating module to approach or move away from the flywheel so as to adjust the magnetic intensity applied to the flywheel.

The operational control unit 50 is electrically connected to the position control device 46 for controlling the operation of the position control device 46, such as transmitting commands to a driving circuit of the electric motor or directly controlling the operation of the electric motor so that the user is able to input commands to the operational control unit 50 via the input device 44, and therefore the operational control unit 50 is able to control the position of the base 62 via the position control device 46 according to the commands for adjusting the resistance level of the flywheel 20, that is, to adjust the resistance level of the pedaling exercise. According to the prior art, the operational control unit 50 is able to receive the present position of the base based on the commands to the position control device 46, the feedback from the position control device 46 (such as number of turns, angular position of the motor or gear set), or by means of sensing devices (not shown) that can sense the position of the base 62 to obtain the present position of the base 62 so as to know the resistance level applied on the flywheel by the magnetic field generating module 66.

As shown in FIG. 1, the support member 64 is extended horizontally in a state where no external force is involved, and its second portion (left end in the figure) is located at an initial position relative to the base 62 to support the magnetic field generating module 66 at a corresponding position. As shown in FIG. 2 and FIG. 3, the support member 64 is flexible, that is, the support member 64 could be bending-deformed between two opposite ends (namely the first portion and the second portion) such that the support member 64 can return to its previous shape by its elasticity. Since the first portion of the support member 64 is fixed to the base 62, it means that the second portion of the support member 64 would be displaced relative to the base 62 as the deformation occurs, and vice versa. When the support member 64 is deformed, or when the second portion of the support member 64 is departed from the initial position, the elastic force of the support member 64 itself would be increased simultaneously to make the support member 64 tend to return to its previous state where no external force is involved. In other words, the elastic force is configured to bias the second portion of the support member 64 to return to the initial position. In the preferred embodiment of the present invention, the support member 64 is a metal plate having a predetermined thickness, or a metal plate having an increased thickness by choice. The metal plate defines two opposite surfaces facing upward and downward respectively in a thickness direction. The metal plate defines a longitudinal direction corresponding to the front-rear direction (the left-right direction in the figure), and the first portion and the second portion are defined at opposite ends of the metal plate in the longitudinal direction, so that the second portion is easily displaced in a vertical direction. Furthermore, the support member 64 and the base 62 may be fixed by means of welding, riveting, or the like, or they may be integrally molded.

The magnetic field generating module 66 applies a (contactless) drag force to resist the rotational motion of the flywheel 20. Therefore, when the user pushes the pedals 16 to rotate the flywheel 20, the magnetic field generating module 66 will be pushed relatively by a (contactless) force in a rotational direction of the flywheel 20 such as an upward force in above relationship. As shown in FIG. 2 and FIG. 3, based on the elastic deformation ability of the support member 64, when the flywheel 20 obtains the torque from the user and overcomes the magnetic resistance (and friction resistance, etc.) for rotation, the second portion of the support member 64 would be displaced upward since the magnetic field generating module 66 is pushed by the upward force from the flywheel 20, namely the support member 64 is bent upwardly. Suppose the other conditions are the same, the greater the torque of the flywheel 20 is, the more force can resist the elastic force of the support member 64 such that the bending deformation of the support member 64 is increased. In contrast, as the torque of the flywheel 20 is decreased, the bending deformation of the support member 64 is decreased. Based on the elastic recovery force of the support member 64, the deformation of the support member 64 is reduced as the torque of the flywheel 20 is increased. When the flywheel 20 stops rotating without any torque, the support member 64 will return to the initial state as shown in FIG. 1.

The stationary bike further comprises a first measuring device 70 for measuring a value of a first parameter. The first parameter represents the displacement amount of the second portion of the support member 64 departing from the initial position, or in correspondence with the displacement amount. For example, in the preferred embodiment of the present invention, the first measuring device 70 includes a strain gauge 72 mounted on the top surface of the support member 64. When the support member 64 is bent, the resistance value between the two ends of the strain gauge 72 (substantially a resistance circuit) will have a corresponding change. Therefore, based on the general application of the strain gauge, the first measuring device 70 uses the strain gauge 72 as a variable resistance and cooperated with other circuits (such as cooperated to form a Wheatstone bridge), amplifier, voltmeter, etc., it can accurately measure the degree of the bending deformation of the support member 64. That is, in the preferred embodiment, the first parameter corresponds to the bending deformation amount of the support member 64, and the bending deformation amount has a corresponding relationship with the displacement amount of the second portion of the support member 64 departing from the initial position. However, in other possible embodiments of the present invention (without corresponding figures), the first measuring device 70 may measure the displacement amount of the second portion of the support member 64, the displacement amount of other portion of the support member 64, or the displacement amount of the magnetic field generating module 66 in other manners as the first parameter. In short, the value of the first parameter corresponds to the magnitude of the torque of the flywheel 20.

It should be noted that, in order to effectively express the measuring principle in the preferred embodiment, the degree of the bending deformation of the support member 64 is exaggerated in FIG. 2 and FIG. 3 to clearly present the upward displacement of the second portion of the support member 64 (it may shift a few millimeters or even more than a centimeter). However, in the present invention, the term “deformation” or “displacement” may occur in addition to the scale that can be recognized with naked eyes, and may also occur to the scale that the human is difficult to recognize with the naked eyes but it can be measured by suitable measuring devices such as strain gauge or piezoelectric sensor.

Referring back to FIG. 1, the first measuring device 70 is electrically connected to the operational control unit 50 for transmitting the value of the first parameter (its corresponding signal) to the operational control unit 50 so that the operational control unit 50 is capable of obtaining a value of a predetermined function by using at least one parameter value including the value of the first parameter. The predetermined function is an applied force that the user drives the pedals 16, or in correspondence with the applied force. For a simple example, when the user pedals the pedals 16 to rotate the flywheel 20, the torque of the flywheel 20 is substantially in proportion to the torque which the user applies on the pedal assembly 10 (note: transmission losses and other energy losses can be corrected in the calculation). Furthermore, the amount of the bending deformation of the support member 64 has corresponding relationship with the torque of the flywheel 20. Therefore, the operational control unit 50 is able to substitute the value of the first parameter (corresponding to the deformation) into a predetermined calculation formula to calculate the output force that the user applies to the motion system and displayed on the display device 42 for allowing the user to view such information. The unit can be newton, or appropriately converted into kilogram, pound, or the like for friendliness. The calculation formula may include constants about the transmission ratio, the energy loss, the proportion of the deformation of the support member and the torque of the flywheel, or it may also contain other arithmetic parameters.

Relative to the instantaneous calculation, the operational control unit 50 may use the value of the first parameter as an index value (there may be other index parameters) to quickly identify the corresponding output force in a predetermined contrast table, or combine with interpolation method to obtain the output force if necessary. The contrast table can be established by a technique similar to the field of prior art, that is, driving the pedal assembly 10 by a driving device and recording the correspondence between the output of the driving device and the resistance level, the flywheel rotational speed, the first parameter (e.g. the bending deformation of the support member 64), etc.

As mentioned before, in the preferred embodiment of the present invention, the drag force applied to the flywheel 20 by the magnetic field generating module 66 is adjustable, namely, by controlling the base 62 to drive the magnetic field generating module 66 to approach or move away from the flywheel 20, the drag force will be increased or decreased correspondingly. For example, suppose the rotational speed of the flywheel 20 is constant (note: the faster/slower the rotation of the flywheel 20, the greater/lesser the drag force and the eddy current), the rotational resistance of the flywheel 20 in FIG. 2 is relatively small, and the rotational resistance of the flywheel 20 in FIG. 3 is relatively large. The greater the resistance of the flywheel 20, the greater the force exerted by the user on the pedals 16 to drive the flywheel 20. For example, suppose the rotational speed of the flywheel 20 is constant, the flywheel 20 in FIG. 3 obtains more torque from the pedal assembly (not shown in FIG. 2 and FIG. 3) than the flywheel 20 in FIG. 2. In other words, although the bending deformation of the support member 64 in FIG. 2 and FIG. 3 are the same, the output force of the user in the state of FIG. 3 is larger than the output force in the state of FIG. 2. In the preferred embodiment of the present invention, since the position of the base 62 substantially determines the rotational resistance of the flywheel 20, the position of the base 62 is also one of the arithmetic parameters/index parameters used to calculate the output force of the user. In other words, the operational control unit 50 is configured to measure the value of the specific function (e.g. the output force of the user) by using at least two parameter values including the value of the first parameter and the position of the base 62.

The stationary bike further comprises a second measuring device 80 for measuring a value of a second parameter. The second parameter represents the rotational speed of the flywheel 20 or in correspondence with the rotational speed. For example, in the preferred embodiment of the present invention, the second measuring device 80 includes a light emitter and a light sensor (not shown) mounted to the frame for sensing angular displacement of an annular grating (not shown) coaxially fixed to the flywheel 20 per unit time so as to measure the rotational speed of the flywheel 20, and such technique is well known in the prior art. In other possible embodiments of the present invention (without corresponding figures), the second measuring device 80 may measure the motion rate or period of any one element of the pedal assembly 10 or the transmission mechanism in similar manner or other manners as the aforementioned second parameter.

The second measuring device 80 is also electrically connected to the operational control unit 50, which is able to transmit the measured value of the second parameter (its corresponding signal) to the operational control unit 50, so that the operational control unit is able to calculate exercise power, metabolic equivalent, calorie consumption rate, etc. of the user by using the value of the second parameter on the basis of above calculation for the output force of the user and displayed on the display device 42 for allowing the user to view such information. At the same rate of motion (e.g. the rotational speed of the pedals is the same in the present embodiment), the more/less the output force of the user, the higher/lower the value of motion rate, metabolic equivalent, calorie consumption rate, etc. Therefore, the aforementioned motion rate, metabolic equivalent, calorie consumption rate, etc. are also “the predetermined function about the output force of the user”.

For the aforementioned description, the exercise apparatus of the present invention is capable of practically measuring the specific parameter corresponding to the force endured by the motion system during exercise for relatively accurately measuring the output force that the user applies to the motion system or further obtaining motion rate, metabolic equivalent, calorie consumption rate, etc. In addition to the stationary bike as disclosed in the preferred embodiment, the present invention is also applicable to other various kinds of exercise apparatuses that require the user to drive a moving member for a specific movement, such as an elliptical trainer, a rowing machine, a non-electric treadmill, a stepper machine, a hand driving exercise machine (e.g. commercial product “Krankcycle®”), various weight training machines. However, the present invention may also be applied to other types of exercise apparatuses not listed. Each motion system of above exercise apparatuses includes at least one moving member (e.g. pedals, handles, running belts), a flywheel and a transmission mechanism connected between the moving member and the flywheel such that the moving member is driven by the user to rotate the flywheel. The motion system of each exercise apparatus is relevant to the prior art, and the detailed description is not mentioned in the present invention.

Each of the exercise apparatuses further comprises a magnetic resistance system for applying a predetermined resistance to the flywheel by using magnets. Typically, the use of magnets and a flywheel to form an eddy current brake (ECB) and thereby to adjust the resistance by controlling the magnetic intensity of the magnets applied to the flywheel is a conventional technique that is well known in the art. In addition to the manner in which the preferred embodiment is used (i.e. the opposite permanent magnets are disposed at two sides of the flywheel in the axial direction and the resistance is adjusted by controlling the working area of the magnets facing toward the flywheel), it may only provide one permanent magnet at one axial side of the flywheel. Furthermore, the magnet may radially approach or move away from the axis of the flywheel, or it may axially approach or move away from the circular plane of the flywheel. Another very common way is that the permanent magnets are arranged at the outer periphery of the flywheel (generally arranged in an arc shape) and adjacent to the outer peripheral surface of the flywheel for increasing or decreasing the resistance of the flywheel by controlling the magnets toward or away from the outer peripheral surface. Furthermore, in contrast to the use of permanent magnets to generate a magnetic field for exerting a drag force opposing the rotational motion of the flywheel, the prior art also uses electromagnets to generate a required magnetic field. For example, a solenoid (often spirally wrapped around a metal core) is arranged adjacent to the outer peripheral surface of the flywheel, which produces a magnetic field with intensity proportional to the current value when a controlled direct current passes through the solenoid, so that the flywheel through the magnetic field must overcome the magnetic resistance therebetween during rotation. Whatever the permanent magnet or the electromagnet, in addition to be arranged at outer periphery of the flywheel, it is also possible that the flywheel has a convex ring protruded axially and the magnet is arranged at inner periphery of the convex ring. The structure and principle of various magnetic resistance systems in the prior art can be appropriately applied in the present invention.

For example, the magnetic field generating module 66 in above preferred embodiment may be substituted by an electromagnet (not shown), and replacing the position control device 46 for controlling the position of the base 62 with an electric current control device (not shown). The electric current control device is able to apply direct current (DC) to the electromagnet and to control the current magnitude of the direct current for controlling the magnetic intensity applied to the flywheel 20 namely controlling the rotational resistance of the flywheel 20. Since the base 62 has no need to move forward and backward, it can be fixed to frame. In other words, the first portion of the support member 64 would be fixed to a specific part of the frame (such part is regarded as a base). Since the electromagnet exerts a drag force against the rotational motion of the flywheel 20, it would be pushed relatively by the force in the rotational direction of the flywheel 20 to make the first portion of the support member 64 produce a corresponding displacement, namely the support member 64 is deformed correspondingly and the first measuring device 70 would obtain a corresponding first parameter. The magnitude of the current applied to the electromagnet substantially determines the rotational resistance of the flywheel 20, and therefore the operational control unit 50 will obtain the value of the specific function by using at least two parameter values including the value of the first parameter and the current value of the current.

Incidentally, the main object of the present invention is to measure the exercise output or the exercise power of a user for a motion system with resistance, and it is not limited that the resistance of the motion system is adjustable. In other words, the present invention allows the rotational resistance of the flywheel to be unadjustable, namely, if the magnetic field forming the resistance is generated by the permanent magnet, the spatial relationship between the permanent magnet and the flywheel is not adjustable. And if the magnetic field forming the resistance is generated by the electromagnet, the magnitude of the current of the electromagnet is fixed and unadjustable.

Next, referring to FIG. 4, there is shown a schematic diagram of a measuring system according to a second preferred embodiment of the present invention (note: the relation of the parts shown in FIG. 4 in the whole exercise apparatus corresponds to the relation of the parts in FIG. 2 in the exercise apparatus shown in FIG. 1, and the following third and fourth embodiments are the same). The flywheel 20 a, the base 62 a and the second measuring device 80 a in FIG. 4 are substantially the same as the flywheel 20, the base 62 and the second measuring device 80 in the previous preferred embodiment, and such parts will not be described again. The difference between the two embodiments is that the support member 64 a is a rod having front and rear ends. The rear end (first portion) is pivotally connected to the base 62 a via a pivot 65 so that the support member 64 a can be pivotally displaced about the pivot 65 with respect to the base 62 a, namely the front end of the support member 64 a is rotatable with respect to the rear end of the support member 64 a. The magnetic field generating module 66 a is fixed to the front end (second portion) of the support member 64 a for producing a magnetic field that exerts a drag force opposing rotational motion of the flywheel 20 a. The second preferred embodiment of the present invention further comprises an elastic member 67 using a plate spring that is capable of flexible deformation. The elastic member 67 has one end fixed to the base 62 a and the other end abutting against the support member 64 a for providing an elastic force to bias the support member 64 a. As shown in FIG. 4 and FIG. 5, the direction of the elastic force corresponds to the direction that deflects the support member 64 a downward about the rear end of the support member 64 a as the axle center. In a condition of no external force involved, the support member 64 a is biased by the elastic member 67 downward until the support member 64 a is stopped by a retaining 63 of the base 62 a at a horizontal state as shown in FIG. 4. At the same time, the position of the front end of the support member 64 a with respect to the base 62 a is defined as an initial position.

As shown in FIG. 5, when the flywheel 20 a is rotated by the movement of the user, the flywheel 20 a applies an upward force to the magnetic field generating module 66 a, and such force will resist the elastic force of the elastic member 67 applied on the support member 64 a so as to deflect the support member 64 a upward about the rear end of the support member 64 a as the axle center and the deformation of the elastic member 67 is increased simultaneously. The first measuring device 70 a measures the deformation of the elastic member 67 by a strain gauge 72 a mounted on the surface of the elastic member 67 (plate spring) and provides such information to an operational control unit (as described previous) to obtain the output force of the user, the exercise power, etc. The first parameter (i.e. the deformation of the elastic member 67 in the present embodiment) measured by the first measuring device 70 a has a corresponding relationship with the displacement amount of the front end of the support member 64 a departing from the initial position. In other possible embodiments (without corresponding figures), the first measuring device 70 a may use other methods to measure the displacement amount of the magnetic field generating module 66 a, the displacement amount of a specific portion (e.g. the front end) of the support member 64 a, or the deflection angle of the support member 64 a as the first parameter.

Referring to FIG. 6, there is shown a schematic diagram of a measuring system in accordance with a third embodiment of the present invention. The flywheel 20 b and the second measuring device 80 b shown in FIG. 6 are the same as described above. The main feature of the third embodiment is that the magnetic field generating module 66 b is supported at a position adjacent to the rear end of the flywheel 20 b by upper and lower opposing support members 64 b. Each of the two support members 64 b is a helical compression spring, and the axial direction (compression direction) of the spring corresponds to the up-down direction. The lower support member 64 b is connected between the bottom of the magnetic field generating module 66 b and the base 62 b for maintaining an upward elastic force applied to the magnetic field generating module 66 b. The upper support member 64 b is connected between the top of the magnetic field generating module 66 b and the base 62 b for maintaining a downward elastic force applied to the magnetic field generating module 66 b. If the magnetic field generating module 66 b is a permanent magnet, the base 62 b may be movably mounted to the frame of the exercise apparatus for being controlled to approach or move away from the flywheel 20 b. If the magnetic field generating module 66 b is an electromagnet, the base 62 b may be fixed to the frame (or substantially a specific portion of the frame). In a condition of no external force involved, the support member 66 b is supported by the two support member 64 b which are competed with each other.

When the flywheel 20 b is rotated by the movement of the user, the magnetic field generating module 66 b will be pushed by the flywheel 20 b with corresponding longitudinal displacement and the flexible deformation of each support member 64 b changes accordingly at the same time. For example, as shown in FIG. 6, when the flywheel 20 b is rotated in the counterclockwise direction, the magnetic field generating module 66 b is displaced upward by an upward force. Accordingly, the upper support member 64 b is compressed in the axial direction, and the lower support member 64 b is stretched in the axial direction. The first measuring device 70 b is configured to measure the first parameter corresponding to the displacement of the magnetic field generating module 66 b or the deformation of the support member 64 b, and provide such information to the operational control unit (as described previous) to obtain the output force of the user, the exercise power, or the like. For example, a piezoelectric material 68 with a direct piezoelectric effect is provided between at least one support member 64 b and the base 62 b. When the compressive deformation amount of the support member 64 b is changed (i.e. the elastic forced is changed), the piezoelectric material 68 is changed correspondingly by a longitudinal pressure so that the voltage value between the upper and lower ends of the piezoelectric material 68 is changed correspondingly, and the deformation amount of the support member 64 b could be obtained by measuring the voltage value. The deformation amount corresponds to the displacement amount of the connecting portion between the support member 64 b and the magnetic field generating module 66 b, namely the displacement amount of the magnetic field generating module 66 b.

The measuring system in FIG. 6 is applicable to the exercise apparatus in which the flywheel 20 b may rotate in both directions, that is, when the flywheel 20 b rotates in the reverse direction namely clockwise in the figure, the magnetic field generating module 66 b is displaced downward. At the same time, the lower support member 64 b is compressed and the upper support member 64 b is stretched, the change of which is reflected in the voltage value of the piezoelectric material 68.

Referring back to FIG. 1, the measuring system in the first embodiment is also applicable to the exercise apparatus in which the flywheel 20 may rotate in both directions. Continuing to refer to the stationary bike in FIG. 1, the support member 64 is bent upward when the user drives the pedals 16 in the forward direction to rotate the flywheel 20 in the counterclockwise direction, so that the resistance value of the strain gauge 72 on the top surface of the support member 64 is correspondingly reduced. In contrast, when the user drives the pedals 16 in the backward direction to rotate the flywheel 20 in the clockwise direction, the support member 64 is bent downward to increase the resistance value of the strain gauge 72 correspondingly.

Referring to FIG. 7, there is shown a schematic diagram of a measuring system in accordance with a fourth embodiment of the present invention. The flywheel 20 c and the second measuring device 80 c shown in FIG. 7 are the same as described above. The main feature of the fourth embodiment is that the support member 64 c is a piezoelectric material having a direct piezoelectric effect and its bottom (the first portion) is fixed on the base 62 c. The magnetic field generating module 66 c is fixed on the top (the second portion) of the support member 64 c and is adjacent to the flywheel 20 c. According to the magnet type of the magnetic field generating module 66 c, the base 62 c may be stationary relative to the flywheel 20 c, or it may be controllably movable. The first measuring device 70 c is capable of measuring the voltage value between the upper and lower ends of the support member (the piezoelectric material) 64 c as the first parameter. When the magnetic field generating module 66 c is pushed relatively by a downward force from the flywheel 20 c, the pressure on the support member 64 is increased and the voltage value between the upper and lower ends of the support member 64 is increased correspondingly. The aforementioned voltage value reflects the magnitude of the torque of the flywheel 20 c. In this embodiment, the first parameter (said voltage value) corresponds to the flexible displacement of the second portion of the support member (the top plane of the piezoelectric material), except that the flexible deformation and displacement may occur at micro-scale.

Accordingly, the exercise apparatus of the present invention is capable of practically measuring a specific parameter corresponding to the force endured by the motion system during exercise for relatively accurately measuring the output force that the user applies to the motion system or further obtaining motion rate, metabolic equivalent, calorie consumption rate, etc. In addition, the present invention is applicable to various exercise apparatuses having a flywheel and a resistance system, and the device for measuring the output force of the user is relatively simple in structure and low cost.

It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents. 

What is claimed is:
 1. An exercise apparatus for performing an exercise, comprising: a frame; at least one moving member driven by a user to be movable with respect to the frame when the user performs the exercise; a flywheel pivotally mounted to the frame; a transmission mechanism connected between the moving member and the flywheel for driving the flywheel to rotate as the moving member is driven by the user; a base mounted to the frame; a support member having a first portion and a second portion, the first portion connected to the base, the second portion being movable from an initial position to other positions with respect to the base, the support member affected by an elastic force, the elastic force increased as the second portion of the support member departs from the initial position and biasing the second portion of the support member to return to the initial position; a magnetic field generating device fixed to the second portion of the support member and being adjacent to the flywheel, the magnetic field generating device configured to generate a magnetic field for exerting a drag force opposing rotational motion of the flywheel; and a first measuring device for measuring a value of a first parameter, the first parameter representing displacement of the second portion of the support member departing from the initial position.
 2. The exercise apparatus as claimed in claim 1, further comprising a second measuring device for measuring a value of a second parameter, the second parameter representing a rotational speed of the flywheel, an operational control unit configured to calculate values of power, metabolic equivalent or calorie consumption rate by using at least two parameter values including the values of the first parameter and the second parameter.
 3. The exercise apparatus as claimed in claim 1, wherein the magnetic field generating device comprises at least one permanent magnet; the base is movable with respect to the frame between a first position in which the magnetic field generating device is close to the flywheel and a second position in which the magnetic field generating device is away from the flywheel.
 4. The exercise apparatus as claimed in claim 1, wherein the magnetic field generating device comprises at least one electromagnet; the exercise apparatus further comprises an electric current control device for controlling electric current applied to the electromagnet.
 5. The exercise apparatus as claimed in claim 1, wherein the support member is flexible, and the elastic force is generated by deformation of the support member between the second portion and the first portion as the second portion is departed from the initial position.
 6. The exercise apparatus as claimed in claim 5, wherein the first parameter corresponds to the deformation of the support member between the second portion and the first portion.
 7. The exercise apparatus as claimed in claim 6, wherein the support member is plate-shaped, having a surface that is deformed flexibly as the second portion departs from the initial position; the first measuring device comprises a strain gauge mounted on the surface of the support member for sensing the deformation of the surface of the support member.
 8. The exercise apparatus as claimed in claim 1, wherein the first portion of the support member is movably connected to the base for allowing the support member to move with respect to the base; the exercise apparatuses further comprises an elastic member, the elastic member having one end connected to the base or the frame and the other end connected to the support member, the elastic member being deformed as the second portion of the support member departs from the initial position and providing the elastic force to the support member.
 9. An exercise apparatus for performing an exercise, comprising: a frame; at least one moving member driven by a user to be movable with respect to the frame when the user performs the exercise; a flywheel pivotally mounted to the frame; a transmission mechanism connected between the moving member and the flywheel for driving the flywheel to rotate as the moving member is driven by the user; a display device for displaying information to the user; an operational control unit for controlling the information displayed on the display unit; a base mounted to the frame; a support member having a first portion and a second portion, the first portion connected to the base, the second portion being movable from an initial position to other positions with respect to the base, the support member affected by an elastic force, the elastic force increased as the second portion of the support member departs from the initial position and biasing the second portion of the support member to return to the initial position; a magnetic field generating device fixed to the second portion of the support member and being adjacent to the flywheel, the magnetic field generating device configured to generate a magnetic field for exerting a drag force opposing rotational motion of the flywheel; and a first measuring device for measuring a value of a first parameter, the first parameter representing displacement of the second portion of the support member departing from the initial position, the first measuring device electrically connected to the operational control unit; wherein at least one of the information displayed on the display unit which is controlled by the operational control unit includes an output force from the user driving the moving member.
 10. The exercise apparatus as claimed in claim 9, further comprising a second measuring device for measuring a value of a second parameter, the second parameter representing a rotational speed of the flywheel, the second measuring device electrically connected to the operational control unit, at least one of the information displayed on the display unit which is controlled by the operational control unit including exercise power, metabolic equivalent or calorie consumption rate of the user. 